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Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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Non-spend Blockchain.com

A bitcoin trader opened a blockchain wallet for me and then sent me my profit but it is non-spendable. I know they can no longer get into my account because I changed the password and I have two-step ...
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1answer
12 views

How to subscribe for blockchain webhook

Please how do I get to subscribe to a BTC address to webhook for unconfirmed transactions?
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1answer
35 views

Extract sender ID and recipient ID of a bitcoin transaction

I'm new to this world and I'm trying to learn the blockchain world and especially now I've concentrated du bitcoin-core, I would like to parser and get the various information like the various sites ...
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15 views

In the event of pending computer crash that might corrupt my Bitcoin Core blockchain download. What files can I copy to prevent corruption?

I run Bitcoin core on my windows 10 machine. And occasionally the damn thing shuts off all my applications and corrupts my Bitcoin Core blockchain download. Yes, I know, don't use windows. That's the ...
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2answers
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What happens to the transactions included in the forks?

Let: a) the vector triplet <x,y,z> refer <height, index, parent_index> b) blocks, block100, block110 (of height 1) are mined together and they both refer previous block block00[null] (of ...
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236 views

What is the counterpart of mining when using blockchain for traceability?

Our project is to create a blockchain so that a customer can traceback any registered good (such as food or drugs). The idea is to replace money with product IDs. (ERC721 from Ethereum does not do the ...
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1answer
20 views

A node can publish any block at any time. How? How to publish?

Can anyone tell me what to do to publish if I mined a block
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1answer
9 views

How do I move the blockchain file location on windowns?

I tried to edit the storage information on bitcoin.info but neither the windowns 7 nor the Bitcoin qt could do it (it says that the app can't open the configuration file). So I tried to edit in the ...
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2answers
15 views

Blockchain and ISO/OSI

I've heard blockchain is built on top of the ISO/OSI stack. Does it means blockchain belongs to the layer 7 (Application layer) of the Osi architecture?
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29 views

Is that considered money laundering by Bitcoin in Germany?

Let's say I have 1000 Euro (in German bank account from legal income) because the German bank's interest is 0% so it is not wise to keep money in my bank account. In my home country (3rd world ...
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1answer
16 views

Blcokchain corrupt ledger

What happen to the node if we find that node on blockchain has corrupt ledger? Is the ledger sync with other ledger or get discard.
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1answer
31 views

How to see download sync speed when syncing the Bitcoin 0.17.1 Blockchain on Ubuntu 18?

I'm syncing the bitcoin 0.17.1 blockchain from the beginning on Ubuntu 18 using Bitcoin Core Qt gui client. Is there a way to see the download speed of the Bitcoin Blockchain and how much time I have ...
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418 views

After downloading the entire Bitcoiin blockchain from a torrent, what are my next steps to link it to Bitcoin Core 0.17.1?

I downloaded the entire bitcoiin blockchain into my external mounted drive as seen below and named the directory bcore. I then did a symlink to that folder like this in my home folder (~) location : ...
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1answer
38 views

How does bitcoin broadcast information?

On Bitcoin's Blockchain, how is information transmitted instantly to all other nodes and do nodes 'talk to each other' through an API? Do Blockchain nodes communicate with each other through HTTP ...
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Reliable nightly download of blockchain data

Is there a reliable night download able blockchain file? The sync is now on its 3rd week. And getting slower. Many cpnfigs tried.
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Hyperledger Blockchain hash function and public-key encryption

I am wondering what is a hash function and public-key encryption that uses to sign any transaction in Hyperledger blockchain platform?
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1answer
17 views

Search for BTC transactions by amount range

It is possible to search transactions by amount range using blockchain or other website without having hash, just by range or exact amount?
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38 views

Help needed while studying PIVX! ( hash doesn't match nBits, proof of work failed)

I am studying how a blockchain works and I have successfully forked and generated a genesis block for PIVX. I am stuck at a point and connot get past this. The process was as follows: 1) Code before ...
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1answer
27 views

json-rpc of bitcoin not working for testnet(curl command)

I am trying this command to get transaction from bitcoin testnet: curl --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "gettransaction", "params": ["txId"] }' -H 'content-type: text/...
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1answer
21 views

Can't use bitcoin-cli commands, error message says “could not connect” from localhost

I am simply trying to run bitcoin-cli getinfo on the same machine that my bitcoin node is running on (with bitcoind -daemon) my bitcoin.conf file is as follows: server='1' rpcuser='username' ...
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1answer
26 views

Blockchain endpoint working

I wanna clear this thing that how blocks are retrieved and created in from the nodes using an end point. The end point is basically centralized and have nothing to do with network if i'm not wrong. Is ...
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0answers
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bitcoin-transaction npm showing Bad Request in response

I am using bitcoin-transaction node npm package for transfer satoshi from one address to another on testnet. I have 0.67779124 satoshi in my testnet address. and I want to transfer it to another ...
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0answers
17 views

How to reuse the blockdata download in a ubuntu in a mac?

I have a ubuntu machine which has complete new block data in ~/.bitcoin/, since I need start bitcoind from a mac, I copied all the files from ubuntu to proper location in mac (which is ~/Library/...
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1answer
31 views

Is blockchain really secure to store sensitive data?

Plenty of developers these days trying to decentralise everything. I noticed some developers claim that they are gonna replace email with blockchain technology. johnmcafeeswiftmail, CryptaMail, ...
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0answers
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what is the reason behind “IsInitialblcokDownload()” function in mining.cpp

I've been working on bitcoin blockchain for a while and this question croosed my mind while studying bitcoin-core. Can any one tell in detail what is the reason behind "IsInitialblcokDownload()" ...
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1answer
41 views

Why isn't the block hash used to calculate accumulated work?

Why is this idea flawed? It doesn't seem to be a bad idea at first, because the miners should be incentivized to extend existing chain, instead of to "remine existing blocks", since such "remining" ...
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1answer
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Is there anything called anonymous or private bitcoins?

Are there different types of bitcoins? Is there anything called private or anonymous bitcoin which can not be traced? This question may sound stupid but I am facing this question right now. I have a ...
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2answers
50 views

At which stage is a transaction validated?

Let's say Alice owns 12 BTC in her wallet, and she tries to send 5 BTC to Bob. First the transaction is broadcast to all nodes, then transaction is in the transaction pool. Then miners would choose ...
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2answers
39 views

Is blockchain the only technology for p2p decentralised global network?

Are there any p2p decentralised cross border network structure out there?
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My Bitcoin transaction timed out on CoinGate but payment/BC disappeared and merchant denies receiving it…how can I track it down? [closed]

So I sent a payment from my Blockchain wallet to a merchant late one night last week and found out in the morning it had "timed out" but the BC was gone and there was no option for a refund. ...
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2answers
38 views

How is blockchain stored on disk?

Hi how is blockchain actually stored on disk? I noticed bitcoin uses key store database level DB but what is the structure? https://github.com/bitcoin-core/leveldb-old/blob/bitcoin-fork/doc/...
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2answers
51 views

Is encryption really needed for blockchain to work?

Is it right to say that Bitcoin and other blockchains do not use encryption? I read somewhere that blockchains rely on digital signatures and hash functions but not on encryption, and that encryption ...
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0answers
23 views

How should i start learning code of any cryptocurrency? [duplicate]

I want to learn about the code of cryptocurrency with all it's features including POS and master node features, currently I have XSN code (stake-net coin) and i want to learn it so i can make use of ...
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2answers
44 views

Blockchain data storage

My learning on blockchain is mainly theory based. I have always been under the impression that blockchain is about data processing and data storage which I think this is where I am confused. I have ...
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2answers
37 views

data confidentiality on blockchain

How does blockchain promise data confidentiality when the data is not encrypted? Or data confidentiality is not part of blockchain feature?
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Hide the ID of confidential transactions in blockchain networks

For a confidential blockchain, suppose there are three people which join a series of transactions. To hide the number of transactions among them, they need to do some dummy transactions. Suppose the ...
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1answer
34 views

Is hashing an optional step to use with public key cryptography for blockchain

I am confused by the public key cryptography versions that I've read so far. Are the steps optional, dependable on the types of blockchain or they are referring to different methods? Version 1 =======...
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1answer
233 views

Why a flip a bin before hashing in this script?

From How can I make this PHP merkle root script recursive? function binFlipByteOrder($string) { return implode('', array_reverse(str_split($string, 1))); } Why a flip?
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Why Spectre has a “weak” liveness?

According to this article: (https://medium.com/@avivzohar/the-spectre-protocol-7dbbebb707b5) written by one of Spectre's author (Aviv Zohar), it is mentioned that Spectre has weak liveness. What is ...
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1answer
46 views

How do different implementations of the Bitcoin Cash client know which type of coin they're processing?

TL;DR: Where in this code does the SV client figure out that it's not processing an ABC blockchain? This image prompted my question. There are a couple different mutually incompatible (I am assuming ...
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1answer
31 views

How Spectre tolerates spam transactions?

Spectre is a DAG based (directed acyclic graph) distributed ledger (a structure as an alternative to blockchain based distributed ledger). Is there any mechanism in Spectre to prevent sending spam ...
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1answer
39 views

Is there a way I can reach the owner of the wallet address

I mistakenly sent some bitcoins to a wrong address. The mistake was from the wallet address I was given. An extra letter was added, making the address 35 digits. Is there a way I can reach the owner ...
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1answer
228 views

BCH ABC testnet Faucet?

I want a bitcoin cash ABC chain (BCHABC) testnet faucet. Cause 15th Nov. onwards after a hard fork on bitcoin cash network existing bch faucets are not working. Even questions over here are also not ...
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1answer
297 views

Why would running a light node riskier and subject to more frauds than a full node? We don't NEED a full ledger, do we?

I've been reading on light node and many have pointed out that the light node doesn't have the full blockchain and is riskier because they can't verify the transactions fully. First, we can verify ...
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Why can't an ISP ban access to a blockchain network? [duplicate]

I read that blockchain sits on top of the internet and is decentralised. We still have to access the blockchain network via an ISP. Without ISP, we can't access the internet so why can't an ISP block ...
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0answers
41 views

Sybil attack with IOTA?

IOTA is one of the DLTs uses DAG (Directed Acyclic Graph) as data structure. The solutions to attacks proposed by IOTA white paper seems unconvincing, in particular, in case of double-spending, it ...
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1answer
85 views

Why is a “first seen” rule is used to pick a side in a honest split, instead of deterministic criteria? [duplicate]

I was just thinking, why nodes pick the first block they see when there is an honest split, instead of picking, for example, the one with the "best hash" (number further away from the difficulty cut)? ...
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1answer
49 views

how to see bitcoin blockchain and addressess for testnet [duplicate]

in my site the user has a link to check the transactions and his wallet address. right now I am using this: blockchain: https://blockchain.info/tx/#{txid} address_url: https://blockchain.info/...
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2answers
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I am just wondering what are the methods which can hide all the transactions and also able to validate transactions in an block chain?

I am new to block chain and was looking at how block chain work mainly proof of stake based . They check validity by going through all the transactions which is something concerning as everyone can ...
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logic behind bitcoin exchange [closed]

Im currently working on exchange program. Just a problem during exchange process. An example, we have an SELLING LIST which list down all trading and selling of bit coin. So, in the meantime, there ...